1. Field of the Invention
The invention generally relates to a fin-type field effect transistor (FinFET), and more particularly, to a method for manufacturing multiple fins having a dense pitch.
2. Description of the Related Art
A fin-type field effect transistor (FinFET) is a type of transistor that has a fin, containing a channel region and source and drain regions. A double-gated FinFET is a FinFET with gate conductors on both sidewall of the fin. The gate conductors cover the channel region of the fin, whereas the source and drain regions of the fin extend beyond the coverage of the gate conductors. FinFETs are discussed at length in U.S. Pat. No. 6,413,802 to Hu et al. (hereinafter “Hu”), which is incorporated herein by reference. FinFETs may comprise only front and/or back gate conductors. Front gate conductors are generally isolated from any conductive material in the substrate and contacts to front gate conductors are etched from above. Back gate conductors are generally electrically connected to a conductive material in the substrate and contacts to the back conductors are etched from below. In order to improve upon current technology, manufacturers are continuously striving to increase the density of devices on integrated circuits and to simultaneously decrease the cost of producing the integrated circuits without adversely affecting performance. FinFET processing is often accomplished using a silicon-on-insulator (SOI) wafer due to the need for isolation of front gates and the ease of defining the fin height. Disadvantages of processing FinFETs in this manner include the high cost of SOI wafers and limitations on device scaling, and particularly, limitations on pitch between devices.